Scientists at two European Union agencies have combined their expertise to analyse Member State data and compile the first joint EU report on antimicrobial resistance in zoonotic bacteria affecting humans, animals and food. Compiled by the European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC), the report indicates that resistance to antimicrobials was observed in zoonotic bacteria, such as Salmonella and Campylobacter, which may cause infectious diseases transmissible between animals and humans and which can be found in foods. The report also presents antimicrobial resistance data for non-disease causing bacteria such as indicator E. coli and Enterococci, that usually do not cause disease in humans.
The report makes an important contribution to current work being carried out at European level and the findings will be considered by the European Commission as it develops its forthcoming proposals for action to fight antimicrobial resistance.
“EFSA has joined ranks with ECDC and Member States to provide policymakers with this important benchmark report,” said Dr Hubert Deluyker, EFSA’s Director of Risk Assessment and Scientific Assistance.
“Recognising the important public health threat from antimicrobial resistance, these two agencies, in close collaboration with their colleagues in various other institutions in Europe, are leading the way in harmonising methodologies for data collection across the EU from the medical, veterinary and food sectors.”
ECDC Director, Marc Sprenger, added “Our shared aim is to harmonise the surveillance and monitoring of antimicrobial resistance in infections that are transmitted between animals and humans. This information is critical to inform decisions on the control of antimicrobial resistant infections that affect a growing number of people across Europe”.
Antimicrobials are used in human and veterinary medicine to eliminate micro-organisms causing infections, such as bacteria. In food-producing animals, the antimicrobials used to treat various infectious diseases may be the same or similar to those used for humans.
Resistance to antimicrobials occurs when the micro-organisms develop mechanisms that reduce their effectiveness or render their use ineffective. Resistant bacteria can spread through many routes. When antimicrobial resistance occurs in zoonotic bacteria present in animals and food it can also compromise the effective treatment of infectious diseases in humans.
The report, based on 2009 data, shows that a high proportion of Campylobacter in humans is resistant to a critically important antibiotic for the treatment of human diseases: ciprofloxacin, which belongs to the fluoroquinolones group. In animals, a high or moderate proportion of Salmonella (in chickens), Campylobacter and non-disease-causing E. coli was also found to be resistant to this antibiotic.
A low proportion of Salmonella in humans and of Salmonella and non-disease-causing E. coli in animals was found to be resistant to third generation cephalosporins, a type of antibiotic, considered by the World Health Organisation (WHO) to be critically important in human medicine.
Key findings of the report
- Campylobacter: In humans, high levels of resistance were recorded for the antimicrobial ciprofloxacin (47%) as well as for resistance to ampicillin (43%) and nalidixic acid (40%). Resistance to another important antimicrobial – erythromycin - was low (3.1%).
- Salmonella: The report shows that resistance to common antimicrobials like ampicillin, tetracycline and sulphonamide was moderate, with around 20% of the tested bacteria considered resistant. Resistance to clinically important antimicrobials - third-generation cephalosporins and fluoroquinolones - was below 10%.
- E. coli: The report did not include data on resistance to antimicrobials in E. coli in humans.
- In animals, Campylobacter also showed high levels of resistance to ciprofloxacin. This was in particular the case for chickens (46% in Campylobacter jejuni and 78% in the Campylobacter coli) and also pigs (50% in Campylobacter coli).
- Salmonella: In animals, high levels of resistance were recorded for ampicillin, tetracycline and sulphonamide in pigs and pig meat (47-60%), cattle (37-40%) and chicken meat (27-33%). A moderate level of resistance to ciprofloxacin was recorded in chickens and chicken meat (around 20%).
- Non-disease causing E. coli showed high levels of resistance to tetracycline, ampicillin and sulphonamide in pigs and chicken; and E. coli was found to be resistant to ciprofloxacin in chicken (47%) and also in pigs (12%). The occurrence of third-generation cephalosporin resistance was still low.
Zoonoses are infections and diseases that are transmissible between animals and humans; of these the most reported are Salmonella and Campylobacter (see EFSA and ECDC annual report on zoonoses). The zoonotic bacteria that are resistant to antimicrobials are of special concern since they might compromise the effective treatment of infections in humans and also in animals.
The European Food Safety Authority and the European Centre for Disease Prevention and Control have analysed the information submitted by 25 European Union Member States (and two non-Member States, Norway and Switzerland) on antimicrobial resistance in Salmonella and Campylobacter isolates from humans, food and animals, and in non-disease causing (indicator/commensal) Escherichia coli and enterococci isolates from animals and food in 2009. Non-disease-causing E. coli and Enterococci are used to indicate the level of antimicrobial resistance in normal bacterial flora in the guts of healthy animals. EFSA has been analysing the resistance to antimicrobials in zoonotic bacteria found in animals and food since 2004.
Fluoroquinolones (such as ciprofloxacin), third-generation cephalosporins (such as cefotaxime), and macrolides (such as erythromycin), are all defined as critically important antimicrobial groups in human medicine by the World Health Organisation.